Voltage controlled oscillators are known in the art, and output a plurality of known frequencies in response to input tuning voltages in accordance with a known voltage versus frequency characteristic curve for that particular VCO. A dedicated potentiometer, or other stable reference voltage source, is used for each channel or preset frequency. For example, 24 frequency channels require 24 tuning voltages, and hence 24 potentiometers. Each potentiometer is calibrated to adjust its output reference voltage to yield the requisite frequency output from the VCO for that channel. For 24 channels, 24 calibrations are needed.
The total time required to calibrate all of the potentiometers is called alignment time. There is a need to reduce this alignment time because it is costly, requires skilled labor, and slows production. There is a further need to reduce alignment time because the alignment process must be repeated periodically. As the VCO ages, or is affected by temperature, etc., each of the potentiometers must be recalibrated, thus repeating the time-consuming alignment of all channels. There is yet a further need to reduce the large amount of hardware and space needed by systems employing a dedicated potentiometer for each channel.